body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
}

header {
  background: #111827;
  color: #fff;
  padding: 1rem;
}

nav a {
  color: #fff;
  margin-right: 1rem;
  text-decoration: none;
}

main {
  padding: 1.5rem;
}